Preparation

• Gather all ingredients.
• Make dipping sauce: Combine mayonnaise, horseradish, ketchup, paprika, salt, black pepper, and cayenne pepper in a small bowl; refrigerate until needed.
• Prepare blooming onion: Beat milk and egg in a large bowl deep enough to dunk onion.
• Combine flour, salt, cayenne pepper, black pepper, garlic powder, thyme, oregano, and cumin in a separate bowl.
• Cut ¾ to 1 inch off top and bottom of onion and remove skin. Remove the 1-inch diameter core from middle of onion.
• Use a large, sharp knife to slice down center of onion ¾ of the way down; turn 90 degrees and slice again.
• Keep slicing each section in half until you have 16 sections. Be careful not to cut through bottom of onion.
• Spread petals apart, dip in milk mixture, then coat well with flour mixture.
• Separate petals again and sprinkle flour mixture between them.
• Dip into milk mixture and flour mixture again. Place battered onion in the refrigerator for at least 15 minutes while you preheat oil.
• Pour enough oil to cover onion into a deep fryer or deep pot. Heat oil to 350 degrees F (175 degrees C). Fry onion right-side-up in hot oil until golden brown, about 10 minutes.
• Drain on a rack or paper towels. Open center of onion wide enough to fit the bowl of dipping sauce and serve warm.